This invention relates to a disc brake, of the kind comprising a brake bracket, a brake disc, an actuation-side ("B-side") brake shoe, an outer-rim-side ("F-side") brake shoe, a brake caliper axially slidably held on the brake bracket, in particular so as to be axially slidable with respect to the brake disc, and which has an outer-rim-side (F-side) caliper arm which extends over the brake disc, a configuration for preventing the F-side brake shoe from rotating along with the brake disc, wherewith by means of said configuration the F-side brake shoe is braced against the brake bracket, a configuration for preventing the B-side brake shoe from rotating along with the brake disc, wherewith by means of said configuration the B-side brake shoe is braced against the brake bracket, and a configuration for preventing the F-side caliper arm from rotating along with the brake disc, wherewith by means of said configuration the [F-side] caliper arm is braced against the brake bracket.
If such a disc brake is actuated while the brake disc is rotating in a given direction, the brake caliper on the F-side tends to move (along with the brake pad) in the direction of the outgoing side ("A-side") of the brake disc, in consequence of the tangential braking force which is being applied and the resulting deformation of the brake bracket; and the brake pad becomes braced against the brake bracket. This movement is accompanied by an inclination of the caliper whereby the brake shoe becomes loaded more heavily on the outgoing side ("A side"), may result in tangential wear of the brake pad of an inclined nature. Further, the inclined orientation of the caliper results in forces, in particular, countertorques, which act on the holding means which hold the caliper on the brake bracket, whereby a risk of jamming arises. On the actuating side ("B side"), the brake bracket tends to be rotated around the configuration by which the brake head is braced on the A side, whereby here inclined tangential wear of the brake pad tends to develop on the incoming side ("E side").
Ger. Pat. 2,919,548 C2 discloses (FIGS. 1 and 6 thereof) an F-side bracing configuration for the brake caliper and the brake shoes with respect to the brake bracket. The bracing therefrom occurs generally on the A side, both for the brake shoes and for the brake caliper. Consequently, all of the tangential braking forces act on one side as to their action on the bracket arm, and thereby they produce a deforming effect on said arm. As a result, inclinations of the caliper unavoidably occur with respect to the F-side brake pad [i.e. with respect to the brake disc on the F side] and with respect to the bolt guide means which hold the caliper.
In the sliding-caliper disc brake according to Ger. OS 23 26 047, means of holding the brake caliper on the brake bracket are provided in the form of bolt guide means, which serve to receive the tangential braking forces which are produced. These bolt guide means extend axially over and beyond the extent of the brake disc. With this structure, there is a risk that the bolts themselves will deform, and thereby the axial slidability of the caliper will be detrimentally affected.
Ger. Pat. 2,750,337 C2 discloses a partial-pad disc brake wherein the means of tangentially and radially guiding the caliper are in the form of "prism guide means" which extend axially over and beyond the brake rotor disc. With prism guide means, very low dimensional tolerances must be met in order to avoid jamming. The F-side brake shoe is attached to the F-side caliper arm, and is braced against the brake caliper guide means (prism guide means) mounted on the brake bracket on the A side. According to Claim 1 of this reference, the caliper arm "positively" and form-interlockingly engages the brake bracket on the E side. According to the stated underlying problem of the invention of this reference, to effectively enhance rigidity this is supposed to divide the F-side tangential forces on the brake head into halves, such that said forces are simultaneously transmitted essentially equally to the E side and A side of the brake bracket. However, in practice this solution is unsatisfactory, because it is essentially impossible to achieve the intended uniform distribution of forces, due to manufacturing tolerances. Bracing of a caliper arm tends to occur only on the E side or else only on the A side, and consequently an inclined orientation of the caliper along with inclined tangential wear of the brake pad can occur.